## 90 Reputation

10 years, 111 days

## Thanks, so it's not possible to make...

Thanks, so it's not possible to make a sequence over 2 indices in seq?

My take was:

## Good...

Thanks. I thought everyone here, except me was a H.Potter ;)

## Maple 2017...

I have 2017 so neither worked. But

plot3d(add(op(1,U(x, t)), n=1..20, 2), x = 0 .. 6, t = 0 .. 4);

worked nice :)

## Could you give some......

examples of how to deal with "unprojected" vectors?

## Many thanks prof. Lopez...

I even managed to get the acceleration right:

Now I can go on with my study of vector calculus with a bit more confidence :)

I just wish though that it would be possible to get the answer explicitly in the new coordinate system. Couldn't find anything in the Physics package. A bit surprising.

## Not quite what I asked for...

Since the unit vectors rho hat and phi hat aren't constant like i hat and j hat they depend on t. So I would like to see e.g the velocity expressed in these unit vectors.

If r(t)=rho(t)*rho hat then

v(t)=rho dot*rho hat+ rho*phi dot*phi hat

How do I get that expression in maple?

## Many thanks for the solution!...

Many thanks for the solution!

## Thanks all for the help...

Thanks all for the help

## @Rouben Rostamian   I'm runnin...

I'm running 2015. Maybe that's why I have to add that

S

## Thanks Rouben...

I suppose you wrote

SetCoordinates(cylindrical[r, phi, z])

otherwise I can't make it work

## @Kitonum  I have Maple 2017 but do...

I have Maple 2017 but doesn't get any solution at all. How is that possible?

S

Thanks!

## @Kitonum  Seems it's not possi...

Seems it's not possible to use ^ in 2d math. Never thought of that.

restart;
z := -(4*b^2*d*p^2-3*c*g*p^2)/(4*(-u+L));
u := 2; L := 1; c := .6;
constr := [1-2*d/(p*(sqrt(g)+1)) <= b, b <= 1, 0 <= d, d <= L, c <= p, p <= u, 1 <= g, g <= 4];
Optimization:-Maximize(z, constr);
[2.20000000000000018, [b = 1., d = 1., g = 1., p = 2.]]

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